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TEXTILESTEXTILES
FORFORPROTECTIONPROTECTION
Keshav Dhawan
B.Tech(Textile Chemistry)-VII Sem
GNDU1
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Contents
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Introduction
Scientific advancements made in various fields have undoubtedly increasedthe quality and value of human life. It should however be recognized that
the technological developments have also exposed us to greater risks and
danger of being affected by unknown physical, chemical and biological
attacks. Fortunately, simple and effective means of protection from most of
these hazards are available. Textiles are an integral part of most protectiveequipment. Protective clothing refers to garments and other fabric-related
items designed to protect the wearer from harsh environmental effects that
may result in injuries or death.
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Classification
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Materials & Technologies
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Steps In The Selection of Protective Clothing
Materials
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Smart Textiles For Protection
Smart/interactive textiles (SIT) are materials and structures that sense and react to
environmental conditions or stimuli, such as those from mechanical, thermal, chemical,electrical, magnetic or other sources.
Smart Textiles can be divided into:Passive smart materials, which can only sense the environmental condition or stimuli.
Active smart materials, which sense and react to the condition or stimuli.
Very smart materials, which can sense, react and adapt themselves accordingly.
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Contribution to Protection
Smart textiles can contribute to Protection and Safety in three ways:
They are able to detect conditions that signal increased danger.They prevent accidents by sending out a warning when hazardous conditions have been
detected.In the case of serious threats they can react by providing instantaneous protection.
Basically, five functions can be distinguished in a smart suit, namely:
Sensing.Data processing.Actuating.
Storage.Communication.
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PolyeletrolyticGels
pH Sensitive Materials
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CHEMICAL PROTECTIVE CLOTHING
FOR
INDUSRIAL WORKERS
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Chemical ProtectionProtective clothing cannot be made generic for all chemical applications, since chemicals vary
in most cases and a particular CPC can protect only against a limited number of specificchemicals.
Important considerations in designing chemical protective clothing are :
The amount of chemical permeation.
Breakthrough time for penetration.
Liquid repellency.Physical properties of the CPC in specific chemical conditions.
Chemical protective clothing can be categorized as encapsulating or non-encapsulating based
on the style of wearing the clothing.
CPC is rated for four levels of protection, levels A, B, C and D from highest protection tonormal protection
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Routes of ExposureInhalation Oral Dermal
NoseLungs
Mouth
Stomach
EyesSkin
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Classification
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Cont..
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Requirements
Chemical Protective Clothing Should Resist : Permeation , Degradation, Penetration.
Durability
Flexibility
Temperature Resistance
Service Life
Clean Ability
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Permeation
Permeation is the diffusion of a chemical on a molecular basis through
chemical protective clothing. This movement of the chemical through the protective material may not be
readily noticeable because it occurs on a molecular or microscopic level. The time it takes the chemical to pass through the protective material until it
is first detected by an analytical instrument is called the breakthrough time.
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Degradation
The change in the physical properties of the material as a result of adverse
effects of the chemical is called degradation.Physical properties may include material weight, dimensions, tensile strength,
hardness. The most common observations of material degradation are Swelling,
Discoloration , Loss of Strength or Deterioration.
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Penetration
Penetration is defined as `the flow of chemical through closures, porous
materials, seams, and pinholes and other imperfection in a protective clothing
material on a non-molecular level.This definition is intended to accommodate both liquids and gases. Penetration of chemicals may take place through Zippers, Seams or
Imperfections in Protective Clothing.
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Materials For CPC
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Textile MaterialsOrdinary textile materials are generally not considered suitable for protection against
chemicals, however special non-coated textile materials are used for a variety of applicationsinvolving particulates and light liquid spray from relatively non-hazardous chemicals.
Though woven textiles are not often found in chemical protective clothing, very tightly woven,
repellent-treated fabrics can provide some very low minimum protection against liquid exposure.
More common are nonwoven fabrics that have demonstrated barrier performance againstparticles and repellency of liquids.
Two predominant examples of non- woven fabrics are flashspun polyethylene (Tyvek) and
spunbond/ meltbown/ spunbond (SMS) polypropylene (Kleenguard).
These textiles are used because of their relatively low cost and because the materials provide astructure of microfibers that filter out dry particulates and many water-based liquids.
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Flash Spun PolyethyleneMade from very fine, high-density polyethylene fibers, lightweight yet strong; vapor-
permeable, yet water- and chemical-resistant, as well as puncture-, tear- and abrasion-resistant.
Tyvek is formed by a fully integrated process using continuous and very fine fibers of 100%
high-density polyethylene that are randomly distributed and no directional. These fibers are first
flash-spun, then laid as a web on a moving bed before being bonded together by heat and
pressure - without the use of binders.
Extensive Temperature Range, Excellent Dimensional Stability: -73C (132C).
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SMS PolypropyleneBreathable fabric multilayered laminate.
The two outer spun bond layers are made of randomly deposited 15 20 micron
diameter continuous polypropylene fibres which provide cloth-like comfort while also
offering fabric strength, durability and abrasion resistance.
The inner melt blown layer provides a filter barrier and is typically comprised of 1-3
micron diameter polypropylene fibres.
The advantage of melt blown as the barrier layer is that it is permeable to both air
and moisture vapour, meaning that both air and sweat vapour can pass through the
garment to keep the skin cool and the wearer more comfortable in hot working
environments.
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4 Advantages of SMS
Provides strength and durability to the garment
Excellent barrier to chemicals and particlesNon-fibrous ultra low lint
Anti-static to EN1149-1Non-woven
Film
The melt blown barrier layer provides a great deal of particulate and liquid protection.
Bonded together, these layers result in a tough cloth-like fabric that provides a high degree
of protection and comfort. 23
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Unsupported Rubber and Plastic Materials
Normally, chemical protective clothing materials include supporting textile fabrics to
provide strength.
However, there are some CPC materials that do not include a fabric substrate. The
rubber material or plastic is thick enough to provide sufficient strength for clothing use.
Examples of polymers used in these materials are polyvinyl chloride and chlorinatedpolyethylene.
Because the materials are continuous, they offer a barrier to liquids and can be used
in the construction of CPC intended for protection against liquids and gases.
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Micro Porous Film-Based Materials
Microporous films have millions of microscopic pores per square inch of the film
structure.In most cases, the pores are irregularly shaped with tortuous paths through the film.This material feature makes the film `breathable' .The microporous films are generally glued or laminated to woven or nonwoven
fabrics for physical support.
Owing to their physical structure, these fabrics provide barrier performance againstliquids but not gases.
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Adsorbent-Based Materials
These materials include adsorbents, such as activated charcoal or other sorbent
materials.Activated Carbon :Activated carbon in very fine powder or granular form is usefulto purify both water and air. Activated carbon has particular affinity to organic
materials such as solvents used in printing inks and common coatings.
(a) Granular (b) Fibrous
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Cont..
Development of Chemical Protective Clothing:
The chemical protective clothing is formed by five layers, the outer shell made ofpolyester as it has low absorption of 2% and it provides a good strength to the fabric
and polyester has a good resistance to lab grade chemicals. The inner layer is made up
of cotton fabric as it gives good absorbency and comfort. The middle layer comprises
of cotton non woven sandwiched with activated carbon.
The polyester fabric has 2% absorption, to avoid penetration of liquid chemicals
through the fabric; the fabric is finished with water repellent chemical NUVA HPU
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Water Repellent Finishing of PET
Nuva HPU
1. Appearance - Liquid, milky-white dispersion
2. Chemical character - Dispersion of a flour compound
3. Ionic character - slightly cationic
4. pH - about 4 (5% as supplied aqueous)
Recipe:
Nuva HPU : 50 gpl
Acetic acid : 0.5 1.5 ml/l
Procedure:
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TECHNIQUE OF EMBEDING ACTIVATED
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TECHNIQUE OF EMBEDING ACTIVATED
CARBONThe carbon used had the following specifications :
Carbon Tetra Chloride Adsorption % 75-85Apparent Density gm/cc 0.42 - 0.47
Ash Content (Max) % max 2.5
Ball - Pan Hardness Number 96.5+
pH 9-11
Surface Area sq. M/gm 1300 1400
Size of granules 0.85 X 0.300 mm
The conventional chemical protective clothing was based on embedding activated carbon using
adhesives and polyurethane foam with a activated carbon load of 120 160 GSM.
These fabrics had low comfort properties of air permeability and thermal comfort causingstress to the wearer.
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N dl P hi T h l
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Needle Punching Technology
The novel technique of embedding activated carbon uses a base fabric made of 100 % cotton and
needle punched cotton non-woven.
The activated carbon granules coated over the double pass needle punched fabric gets embedded
in the non-woven. The cotton fibers dose not allows the carbon granules to move from its place.The activated carbon coated non woven had a GSM of 341. 30
C t N dli
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Cont.. Needling
The fabric thus prepared was fed in to the needle punching machine through a pair of
conveyors and calendar rollers.To provide a initial cohesion to the layers a pressure of 6 bar was maintained at front and back
pair of calendar rollers.The web was fed such that the cotton woven fabric as the top layer.
The fabric layers were needle punched with following settings:
In feed speed 0.4 m /min
Draw off speed : 0.4 m/ min
Strokes / min : 152
Depth : 15 mm
Width : 700 mm
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B di f N W & PET F b i
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Bonding of Non-Woven & PET Fabric
The activated carbon sandwiched non woven and polyester fabric are bonded
together using acrylic resin.Acrylic resin provides a good strength along with flexibility.The fabric is placed on a platform and the resin is uniformly sprayed on the
fabric using a hand spray gun . The cotton non woven is placed over the fabric and the fabric is applied with
uniform pressure. Thus prepared fabric is cured at 110 0C for 2 min.
The maximum penetration was in case of acetone and it was 0.4 %,
while the no penetration in case of hydrogen peroxide and sodium
hydroxide.The maximum permeation was in case of dichloromethane and it was
10.79%, while no permeation in case of sulphuric acid.
The maximum degradation was in case of sulphuric acid and theweight loss of the fabric was 18.60%, while no degradation in case of
sodium hydroxide, Hydrochloric acid and Dimethyl Formamide.
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M t i l F CPC C t
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Material For CPC .Cont
Coated fabrics:Materials using this construction tend to be heavy, but relatively rugged and are used in a variety
of chemical protective clothing. Today, the most common clothing using coated fabrics are
splash suits, but some higher-end totally encapsulating suits may be made from coated fabrics.
Plastic laminates :These materials combine various plastic polymer films with nonwoven substrate fabrics resulting
in chemical-resistant, lightweight, relatively inexpensive materials. The majority of substrates arebased on polypropylene and films are based on polyethylene and polyvinyl alcohol polymers, but
more sophisticated films may employ a variety of different plastic films in a single laminate.
Combination or specialized materials:These fabrics generally attempt to combine the best attributes of each class. For example, coated
fabrics have been laminated with a plastic film on one side to provide the flexible featuresassociated with rubber-based fabrics and the high levels of chemical resistance. Microporous
films can be combined with adsorbent-based materials to provide a film with liquid chemical
resistance that adsorbs large molecular weight chemical vapors.
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G t D i F t
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Garment Design Features
The type and location of Seams.
The type, length, and location of the closure system(s).
The type and characteristics of visors or face shields, if integrated into garments.
The design of interface areas with other chemical protective clothing or equipment.
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S
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Seams
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Cl S t
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Closure Systems
Closures are typically the `weak' link in the chemical protective clothing barrier.
The simplest closures are zippers or a series of snaps.CPC designs use storm flaps to cover the zipper or snaps.
Liquid-repellent zippers are conventional zippers that use rubber or plastic coated tape instead
of woven cloth on the sides of the zipper and that have a special chain (teeth) that are coated to
limit liquid penetration.
Two-track closures involve two extruded pieces of plastic that fit together to provide a seal much
like many plastic sandwich bags. These closures offer good integrity against liquids (and vapors)
but can be difficult to seal over a long length .
The pressure-sealing zipperuses a compressible rubber or plastic material with a zipper chain
to push the two sides of the closure material together for creating a seal. These zippers tend to be
bulky and expensive but are generally required when total encapsulation of the wearer is
required.
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G t Vi
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Garment Visors
Visors are generally incorporated into suits to offer chemical barrier protection for the head and
face area. In general, the visor is constructed from a material that provides clear undistorted
vision as well as chemical resistance.
The principal materials used in visor construction are polyvinyl chloride, polycarbonate, and
polymethacrylate.Since the visor material must provide optical qualities, only transparent materials can be
chosen as visors.
When greater chemical resistance is required, the visor made be made of a composite material
that includes fluorinated ethylene propylene (FEP) laminated to PVC.
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I t f A
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Interface Areas
Principal CPC Interfaces include:Amount of overlap for multi-piece garments.
Upper torso garment sleeve to glove.Lower torso pant cuff to footwear.Upper torso garment collar to hood.Hood to respirator.
If different pieces of chemical protective clothing are worn, the items should provide sufficient
overlap to cover the wearer's skin particularly during bending over.
Elasticized sleeve ends provide somewhat better conformance of the sleeve with the glove.A straight cuff is used. The cuff is generally pulled over the boot to keep liquid from entering
the top of the boot or footwear.
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L l f Ch i l P t ti
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Levels of Chemical Protection
In Hazardous Material operations there are four levels of protection.
Level A
Level B
Level C
Level D
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L l A
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Level A
Fully encapsulating suit with self-contained breathing apparatus.
Level A should be worn when the highest level of respiratory, skin, and eye
protection is required.
Level A is used when:
Conditions are unknown.
The hazardous substance has been identified and requires the highest level
of protection for skin, eyes, and respiratory system.Operations are being conducted in confined, poorly ventilated areas.
Work function involves a high potential for splash, immersion, or
exposure to unexpected skin hazards .
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Le el B
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Level B
Self-contained breathing apparatus, Chemical protective clothing,
gloves, and hard hat.
Should be selected when the highest level of respiratory protected is
needed and some degree of skin protection is required. Level B is
the minimum recommendation for initial site entry.
Level B protection is used when:
Air contaminants are unknown.
Air contaminants have been identified and the criteria for using
APRs are not met.
The atmosphere contains less than 19.5% oxygen.
Direct contact does not pose a severe skin hazard.
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Level C
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Level C
Air-purifying respirator, chemical protective clothing, gloves, boots, and
hard hat.
Level C should be selected when types of airborne contaminants
are known, the concentrations are measured and the criteria for
using air-purifying respirators (APRs) are met.
Level C protection is used when:
Criteria for the use of APRs are met.
Air contaminants have been identified and concentrations
measured.
Direct contact does not pose a skin hazard.
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Level D
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Level D
Chemical-protective clothing, boots, gloves, and hard hat.
Level D should not be worn on any site with respiratory or skin hazards.
Level D is primarily a work uniform providing minimal protection.
Level D protection is worn when:
Atmosphere contains no known hazards.
Work functions precludes the potential for unexpected exposure
to hazardous levels of any substances.
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Ulti t P d t
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Ultimate Product
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Various Test Method For CPC
ASTM F1186-03
ASTM F1001-99aASTM F739-99aASTM F1383-99aASTM F1407-99a
ASTM F1194-99ASTM F903-03ASTM F2053-00
ASTM F2130-01
EN 943-1:2002EN 467:1995EN374-3:1994EN ISO 6529
ISO 6530 (1990)ISO 13994 (1998)ISO 17491(2002)
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Further Reading
Textiles for protection Edited byRichard A. Scott Woodhead, Cambridge.Military textiles Edited by Eugene Wilusz Woodhead, Cambridge.Intelligent Textiles for Personal Protection and Safety Edited by Sundaresan Jayaraman Georgia
Institute of Technology, USA Paul Kiekens Ghent University, Belgium and Ana Marija Grancaric
University of Zagreb.Stull J O, `Selecting chemical protective clothing,' Occup Health & Safety, December 1995, 2024.Abbott N J (2001), `Coated fabrics for protective clothing', in Satas D and Tracton A A., Coatings
technology handbook (2nd edn), Marcel Dekker, 819823.
Hall M E (2000a), `Finishing of technical textiles', in Horrocks A R and Anand S C, Handbook of
technical textiles, Woodhead, Cambridge.Mona Suri, D Rastogi, K.Khanna, Development of protective clothing for pesticide industry: part
I, Indian Journal of Fibre & Textile Research, vol.27, pp. 85-90, march, 2002. www. Scribd.com http://www.kcprofessional.com/us/kcp-brands/kleenguard/kleenguard.asp
http://www.lakeland.com
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Be pro-active not reactive towards safetyBe pro-active not reactive towards safety